SLC26A2 and deafness: Increasing number of genetic variants are associated with various human diseases such as nephrocalcinosis (SLC26A1), hyperoxalemia (SLC26A1), diastrophic dysplasia (SLC26A2), achondrogenesis (SLC26A2), atelosteogenesis (SLC26A2), multiple epiphyseal dysplasia (SLC26A2), congenital chloride diarrhea (SLC26A3), deafness (SLC26A4 and SLC26A5), bicarbonate metabolism-related diseases (SLC26A6), hypothyroidism (SLC26A7), asthenozoospermia (SLC26A8), bronchiectasis (SLC26A9), and dysregulation of chloride homeostasis and neuroactivity (SLC26A11) (1, 2, 3).